Revert, causing browser crashes due to race

content/browser/renderer_host/media/peer_connection_tracker_host.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 #include "content/browser/renderer_host/media/peer_connection_tracker_host.h"
 
-#include "base/power_monitor/power_monitor.h"
 #include "content/browser/media/webrtc_internals.h"
 #include "content/common/media/peer_connection_tracker_messages.h"
-#include "content/public/browser/render_process_host.h"
 
 namespace content {
 
 PeerConnectionTrackerHost::PeerConnectionTrackerHost(int render_process_id)
     : BrowserMessageFilter(PeerConnectionTrackerMsgStart),
-      render_process_id_(render_process_id) {
-  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
-  if (power_monitor)
-    power_monitor->AddObserver(this);
-}
+      render_process_id_(render_process_id) {}
 
 bool PeerConnectionTrackerHost::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
 
   IPC_BEGIN_MESSAGE_MAP(PeerConnectionTrackerHost, message)
     IPC_MESSAGE_HANDLER(PeerConnectionTrackerHost_AddPeerConnection,
                         OnAddPeerConnection)
     IPC_MESSAGE_HANDLER(PeerConnectionTrackerHost_RemovePeerConnection,
                         OnRemovePeerConnection)
     IPC_MESSAGE_HANDLER(PeerConnectionTrackerHost_UpdatePeerConnection,
                         OnUpdatePeerConnection)
     IPC_MESSAGE_HANDLER(PeerConnectionTrackerHost_AddStats, OnAddStats)
     IPC_MESSAGE_HANDLER(PeerConnectionTrackerHost_GetUserMedia, OnGetUserMedia)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void PeerConnectionTrackerHost::OverrideThreadForMessage(
     const IPC::Message& message, BrowserThread::ID* thread) {
   if (IPC_MESSAGE_CLASS(message) == PeerConnectionTrackerMsgStart)
     *thread = BrowserThread::UI;
 }
 
 PeerConnectionTrackerHost::~PeerConnectionTrackerHost() {
-  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
-  if (power_monitor)
-    power_monitor->RemoveObserver(this);
 }
 
 void PeerConnectionTrackerHost::OnAddPeerConnection(
     const PeerConnectionInfo& info) {
   WebRTCInternals::GetInstance()->OnAddPeerConnection(
       render_process_id_,
       peer_pid(),
       info.lid,
       info.url,
       info.rtc_configuration,
@@ skipping 26 matching lines @@
     const std::string& video_constraints) {
   WebRTCInternals::GetInstance()->OnGetUserMedia(render_process_id_,
                                                  peer_pid(),
                                                  origin,
                                                  audio,
                                                  video,
                                                  audio_constraints,
                                                  video_constraints);
 }
 
-void PeerConnectionTrackerHost::OnSuspend() {
-  content::RenderProcessHost* host =
-      content::RenderProcessHost::FromID(render_process_id_);
-  if (host)
-    host->Send(new PeerConnectionTracker_OnSuspend());
-}
-
 }  // namespace content